private static Nonterminal Reduce(ParserStack stack, RuleType rule)
{
// Create a language element array big enough to hold the LHS and RHS
// arguments.
//
int parameterCount = 1 + rule.Rhs.Length;
LanguageElement[] parameters = new LanguageElement[parameterCount];
// Create the LHS nonterminal.
//
Nonterminal lhs = rule.Lhs.CreateNonterminal();
parameters[0] = lhs;
// Pop the RHS language elements off the stack.
//
for (int idx = 0; idx < rule.Rhs.Length; ++idx)
{
parameters[parameterCount - idx - 1] = stack.Pop().LanguageElement;
}
// Invoke the rule.
//
rule.Invoke(parameters);
return(lhs);
}
/// <summary>
/// Adds a new <see cref="ParserStackItem"/> to the <see cref="ParserStack"/>.
/// </summary>
/// <param name="languageElement">The <see cref="LanguageElement"/> associated with this <see cref="ParserStackItem"/>. When created by a shift action,
/// contains the <see cref="Terminal"/> that triggered the action. When created by a reduce action, contains a <see cref="Nonterminal"/>
/// constructed by the <see cref="RuleType.Lhs"/> of the <see cref="RuleType"/> that triggered the action.</param>
/// <param name="state">The <see cref="ParserState"/> that represents the current parsing state when the <see cref="ParserStackItem"/> is the topmost
/// item on the <see cref="ParserStack"/>.</param>
public void Push(LanguageElement languageElement, ParserState state)
{
Push(new ParserStackItem(languageElement, state));
}